Friday, 10 April 2026

PYQ references used by both prompts 28 included

Flagged questions are excluded from both Study Notes and PPT references until corrected in Paper Analyzer.

Included ID 6480 · 2021 · 1 mark(s)

Which of the following operator cannot be used with string data type?
a) +
b) in
c) *
d) /

Revision of Python & Core Concepts → String operations

Included ID 6512 · 2021 · 1 mark(s)

Find the output of the following code:
Name="PythoN3.1"
R=""
for x in range(len(Name)):
    if Name[x].isupper():
        R=R+Name[x].lower()
    elif Name[x].islower():
        R=R+Name[x].upper()
    elif Name[x].isdigit():
        R=R+Name[x-1]
    else:
        R=R+"#"
print(R)
a) pYTHOn##@
b) pYTHOnN#@
c) pYTHOn#@
d) pYTHOnN@#

Revision of Python & Core Concepts → String operations

Included ID 6531 · 2022 · 1 mark(s)

Select the correct output of the code:
a = "Year 2022 at All the best"
a = a.split('2')
b = a[0] + ". " + a[1] + ". " + a[3]
print(b)
a) Year . 0. at All the best
b) Year 0. at All the best
c) Year . 022. at All the best
d) Year . 0. at all the best

Revision of Python & Core Concepts → String operations

Included ID 6535 · 2022 · 1 mark(s)

Which of the following statement(s) would give an error after executing the following code?
S="Welcome to class XII"  # Statement 1
print(S)                  # Statement 2
S="Thank you"             # Statement 3
S[0]= '@'                 # Statement 4
S=S+"Thank you"           # Statement 5
a) Statement 3
b) Statement 4
c) Statement 5
d) Statement 4 and 5

Revision of Python & Core Concepts → String operations

Included ID 6091 · 2023 · 1 mark(s)

Select the correct output of the code :
S= "Amrit Mahotsav @ 75"
A=S.partition (" ")
print (a)
(a) ('Amrit Mahotsav','@','75')
(b) ['Amrit', 'Mahotsav','@','75']
(c) ('Amrit', 'Mahotsav @ 75')
(d) ('Amrit', '', 'Mahotsav @ 75')

Revision of Python & Core Concepts → String operations

Included ID 6288 · 2023 · 1 mark(s)

Select the correct output of the code :
S="Amrit Mahotsav @ 75"
A=S.split(" ",2)
print (A)
(a) ('Amrit', 'Mahotsav', '@', '75')
(b) ['Amrit', 'Mahotsav', '@ 75']
(c) ('Amrit', 'Mahotsav', '@75')
(d) ['Amrit', 'Mahotsav', '@', '75']

Revision of Python & Core Concepts → String operations

Included ID 6292 · 2023 · 1 mark(s)

Which of the following statement(s) would give an error after executing the following code ?
S="Happy" # Statement 1
print (S*2) # Statement 2
S+="Independence" # Statement 3
S.append ("Day") # Statement 4
print (S) # Statement 5
(a) Statement 2
(b) Statement 3
(c) Statement 4
(d) Statement 3 and 4

Revision of Python & Core Concepts → String operations

Included ID 6572 · 2023 · 1 mark(s)

Select the correct output of the code:
s = "Python is fun"
l = s.split()
s_new = "-".join([l[0].upper(), l[1], l[2].capitalize()])
print(s_new)
a) PYTHON-IS-Fun
b) PYTHON-is-Fun
c) Python-is-fun
d) PYTHON-Is -Fun

Revision of Python & Core Concepts → String operations

Included ID 6576 · 2023 · 1 mark(s)

Consider the statements given below and then choose the correct output from the given options:
pride="#G20 Presidency"
print(pride[-2:2:-2])
a) ndsr
b) ceieP0
c) ceieP
d) yndsr

Revision of Python & Core Concepts → String operations

Included ID 6598 · 2023 · 3 mark(s)

Predict the output of the Python code given below:
Text1="IND-23"
Text2=""
I=0
while I<len(Text1):
    if Text1[I]>="0" and Text1[I]<="9":
        Val = int(Text1[I])
        Val = Val + 1
        Text2=Text2 + str(Val)
    elif Text1[I]>="A" and Text1[I]<="Z":
        Text2=Text2 + (Text1[I+1])
    else:
        Text2=Text2 + "*"
    I+=1
print(Text2)

Revision of Python & Core Concepts → String operations

Included ID 6137 · 2024 · 1 mark(s)

What will be the output of the following code ?
S='New Delhi'
S=S.replace('e','*')
print(S)
(A) N*w D*lhi
(B) New Delhi
(C) N*w D*lhi
(D) *ew D*lhi

Revision of Python & Core Concepts → String operations

Included ID 6142 · 2024 · 1 mark(s)

State True or False:
The count() method of a string returns the number of occurrences of a substring in the string.

Revision of Python & Core Concepts → String operations

Included ID 6146 · 2024 · 1 mark(s)

State True or False:
In Python, the upper() method returns the given string by converting all the lower case letters to upper case.

Revision of Python & Core Concepts → String operations

Included ID 6330 · 2024 · 1 mark(s)

Select the correct output of the code :
S = "text#next"
print(S.strip("t"))
(A) ext#nex
(B) ex#nex
(C) text#nex
(D) ext#next

Revision of Python & Core Concepts → String operations

Included ID 6334 · 2024 · 1 mark(s)

Consider the statements given below and then choose the correct output from the given options :
Game="World Cup 2023"
print(Game[-6::-1])
(A) CdrW
(B) ce o
(C) puC dlroW
(D) Error

Revision of Python & Core Concepts → String operations

Included ID 6612 · 2024 · 1 mark(s)

Identify the output of the following code snippet:
text = "PYTHONPROGRAM"
text=text.replace('PY','#')
print(text)
a) #THONPROGRAM
b) ##THON#ROGRAM
c) #THON#ROGRAM
d) #YTHON#ROGRAM

Revision of Python & Core Concepts → String operations

Included ID 6614 · 2024 · 1 mark(s)

What is the output of the expression?
country='International'
print(country.split("n"))
a) ('I', 'ter', 'atio', 'al')
b) ['I', 'ter', 'atio', 'al']
c) ['I', 'n', 'ter', 'n', 'atio', 'n', 'al']
d) Error

Revision of Python & Core Concepts → String operations

Included ID 6615 · 2024 · 1 mark(s)

What will be the output of the following code snippet?
message= "World Peace"
print(message[-2::-2])

Revision of Python & Core Concepts → String operations

Included ID 6356 · 2024 · 3 mark(s)

Predict the output of the Python code given below :
s="India Growing"
n = len(s)
m=""
for i in range (0, n) :
    if (s[i] >= 'a' and s[i] <= 'm') :
        m = m + s [i].upper()
    elif (s[i] >= 'O' and s[i] <= 'z') :
        m = m +s [i-1]
    elif (s[i].isupper()):
        m = m + s[i].lower()
    else:
        m = m + '@'
print (m)

Revision of Python & Core Concepts → String operations

Included ID 6175 · 2025 · 1 mark(s)

Identify the correct output of the following code snippet:
game="Olympic2024"
print(game.index("C"))
(A) 0
(B) 6
(C) -1
(D) ValueError

Revision of Python & Core Concepts → String operations

Included ID 6370 · 2025 · 1 mark(s)

Identify the output of the following code segment:
s = "an apple. a toy."
s=s.find('a',2)
print(s)
(A) 0
(B) 1
(C) 3
(D) 'a'

Revision of Python & Core Concepts → String operations

Included ID 6372 · 2025 · 1 mark(s)

What is the output of the following expression ?
Sports="Paralympic Games"
print (Sports.split("m"))
(A) ['Paraly','m','pic Ga','m','es']
(B) ('Paraly','m','pic Games')
(C) ('Paraly','pic Ga','es')
(D) ['Paraly','pic Ga','es']

Revision of Python & Core Concepts → String operations

Included ID 6665 · 2025 · 1 mark(s)

What will be the output of the following Python code?
str= "Soft Skills"
print(str[-3::-3])
a) lSf
b) Stkl
c) StKi
d) l

Revision of Python & Core Concepts → String operations

Included ID 6674 · 2025 · 1 mark(s)

What is the output of the given Python code?
st='Waterskiing is thrilling!'
print(st.split("i"))
a) ['Watersk', 'ng ', 's thr', 'll', 'ng!']
b) ['Watersk', '', 'ng ', 's thr', 'll', 'ng!']
c) ['Watersk', 'i', 'ng ', 's thr', 'll', 'ng!']
d) Error

Revision of Python & Core Concepts → String operations

Included ID 6686 · 2025 · 2 mark(s)

B. Predict the output of the following Python code:
text="Learn Python with fun and practice"
print(text.partition("with"))
print(text.count("a"))

Revision of Python & Core Concepts → String operations

Included ID 6697 · 2025 · 3 mark(s)

A. Predict the output of the following Python code:
s1="SQP-25"
s2=""
i=0
while i<len(s1):
    if s1[i]>='0' and s1[i]<='9':
        Num=int(s1[i])
        Num-=1
        s2=s2+str(Num)
    elif s1[i]>='A' and s1[i]<='Z':
        s2=s2+s1[i+1]
    else:
        s2=s2+'^'
    i+=1
print(s2)

Revision of Python & Core Concepts → String operations

Included ID 6219 · 2026 · 1 mark(s)

Identify the output of the following code snippet :
s = "the Truth"
print(s.capitalize())
(A) The truth
(B) THE TRUTH
(C) The Truth
(D) the Truth

Revision of Python & Core Concepts → String operations

Included ID 6222 · 2026 · 1 mark(s)

What will be the output of the following statement ?
print("PythonProgram"[-1:2:-2])

Revision of Python & Core Concepts → String operations

.txt

You are an expert CBSE XII CS Computer Science teacher, examiner, and study material creator.

===========================================
SCOPE — READ BEFORE GENERATING ANYTHING
===========================================
Today's lecture covers ONE topic only: "String operations"
Lecture number 8 of 91 | Duration: 35 minutes | Board: CBSE
Chapter: Computational Thinking and Programming – 2

HARD RULE: Every piece of content you generate — notes, examples, questions, tips —
must be directly relevant to "String operations" only.
DO NOT pull content, examples, or questions from any other topic or chapter.

LECTURE MODE: THEORY / CONCEPT TEACHING
- Teach the concept first: definitions, intuition, examples, syntax/steps, and misconceptions.
- Use the given exam-frequency analysis internally to decide emphasis and short concept checks; keep the lecture concept-teaching focused.
- Keep content tightly scoped to today's concept list.

===========================================
SECTION 1: LECTURE INFORMATION
===========================================

Class: XII CS | Subject: Computer Science | Board: CBSE
Topic: String operations Theory
Subtopics to cover today:
- String operations

Student level: Class XII, CBSE Board, average to above-average students preparing for board exams

===========================================
SECTION 2: TEACHER'S REFERENCE NOTES
===========================================

String operations Theory

Concept ID: U1_STRING_OPS.
Primary Sub-subtopic: String operations.
Question-bank grouping: Revision of Python & Core Concepts.

Use this lecture for theory, examples, misconceptions, and short concept checks mapped to this concept ID.

Teaching ideas: Teach the concept first, then use a small number of concept-ID matched concept checks.

===========================================
SECTION 3: EXAM FREQUENCY DATA (Year-wise)
===========================================

Teaching priority: HIGH
High-yield concepts: String operations

| Year | Questions | Marks |
|------|-----------|-------|
| 2021 | 2 | 2 |
| 2022 | 2 | 2 |
| 2023 | 6 | 8 |
| 2024 | 9 | 11 |
| 2025 | 7 | 10 |
| 2026 | 2 | 2 |
| **Total** | **28** | **35** |

===========================================
SECTION 4: EXAM ANALYSIS INPUT — DO NOT PRINT THESE IN THEORY NOTES
(Scope: "String operations" only — 28 questions from board papers)
===========================================

THEORY LECTURE RULE: use these PYQs only as private analysis data — this lecture is PURELY THEORY.
- Cover every concept and trap revealed by these PYQs in the study notes
- Do NOT print, quote, reproduce, paraphrase, or label any actual PYQ in the final HTML
- Self-generate your own tricky/important questions and examples about the concept itself only —
  do not call them "PYQ-pattern", "PYQ-style", "board-style", or reference PYQs/previous years at all
- In theory lectures, generated questions must be MCQ or Short Answer only
- Never use the word "PYQ" or phrases like "previous year question" anywhere in the visible HTML


--- 2021 Board Exam (2 questions | 2 marks) ---

Q1. [MCQ] [1M] [Easy] Section-A
Which of the following operator cannot be used with string data type?
a) +
b) in
c) *
d) /

Q2. [MCQ] [1M] [Easy] Section-B
Find the output of the following code:
Name="PythoN3.1"
R=""
for x in range(len(Name)):
    if Name[x].isupper():
        R=R+Name[x].lower()
    elif Name[x].islower():
        R=R+Name[x].upper()
    elif Name[x].isdigit():
        R=R+Name[x-1]
    else:
        R=R+"#"
print(R)
a) pYTHOn##@
b) pYTHOnN#@
c) pYTHOn#@
d) pYTHOnN@#

--- 2022 Board Exam (2 questions | 2 marks) ---

Q1. [MCQ] [1M] [Easy] Section-A
Select the correct output of the code:
a = "Year 2022 at All the best"
a = a.split('2')
b = a[0] + ". " + a[1] + ". " + a[3]
print(b)
a) Year . 0. at All the best
b) Year 0. at All the best
c) Year . 022. at All the best
d) Year . 0. at all the best

Q2. [MCQ] [1M] [Easy] Section-A
Which of the following statement(s) would give an error after executing the following code?
S="Welcome to class XII"  # Statement 1
print(S)                  # Statement 2
S="Thank you"             # Statement 3
S[0]= '@'                 # Statement 4
S=S+"Thank you"           # Statement 5
a) Statement 3
b) Statement 4
c) Statement 5
d) Statement 4 and 5

--- 2023 Board Exam (6 questions | 8 marks) ---

Q1. [MCQ] [1M] [Easy] Section-A
Select the correct output of the code :
S= "Amrit Mahotsav @ 75"
A=S.partition (" ")
print (a)
(a) ('Amrit Mahotsav','@','75')
(b) ['Amrit', 'Mahotsav','@','75']
(c) ('Amrit', 'Mahotsav @ 75')
(d) ('Amrit', '', 'Mahotsav @ 75')

Q2. [MCQ] [1M] [Easy] Section-A
Select the correct output of the code :
S="Amrit Mahotsav @ 75"
A=S.split(" ",2)
print (A)
(a) ('Amrit', 'Mahotsav', '@', '75')
(b) ['Amrit', 'Mahotsav', '@ 75']
(c) ('Amrit', 'Mahotsav', '@75')
(d) ['Amrit', 'Mahotsav', '@', '75']

Q3. [MCQ] [1M] [Easy] Section-A
Which of the following statement(s) would give an error after executing the following code ?
S="Happy" # Statement 1
print (S*2) # Statement 2
S+="Independence" # Statement 3
S.append ("Day") # Statement 4
print (S) # Statement 5
(a) Statement 2
(b) Statement 3
(c) Statement 4
(d) Statement 3 and 4

Q4. [MCQ] [1M] [Easy] Section-A
Select the correct output of the code:
s = "Python is fun"
l = s.split()
s_new = "-".join([l[0].upper(), l[1], l[2].capitalize()])
print(s_new)
a) PYTHON-IS-Fun
b) PYTHON-is-Fun
c) Python-is-fun
d) PYTHON-Is -Fun

Q5. [MCQ] [1M] [Easy] Section-A
Consider the statements given below and then choose the correct output from the given options:
pride="#G20 Presidency"
print(pride[-2:2:-2])
a) ndsr
b) ceieP0
c) ceieP
d) yndsr

Q6. [Output Prediction] [3M] [Medium] Section-C
Predict the output of the Python code given below:
Text1="IND-23"
Text2=""
I=0
while I<len(Text1):
    if Text1[I]>="0" and Text1[I]<="9":
        Val = int(Text1[I])
        Val = Val + 1
        Text2=Text2 + str(Val)
    elif Text1[I]>="A" and Text1[I]<="Z":
        Text2=Text2 + (Text1[I+1])
    else:
        Text2=Text2 + "*"
    I+=1
print(Text2)

--- 2024 Board Exam (9 questions | 11 marks) ---

Q1. [MCQ] [1M] [Easy] Section-A
What will be the output of the following code ?
S='New Delhi'
S=S.replace('e','*')
print(S)
(A) N*w D*lhi
(B) New Delhi
(C) N*w D*lhi
(D) *ew D*lhi

Q2. [Short Answer] [1M] [Easy] Section-A
State True or False:
The count() method of a string returns the number of occurrences of a substring in the string.

Q3. [Short Answer] [1M] [Easy] Section-A
State True or False:
In Python, the upper() method returns the given string by converting all the lower case letters to upper case.

Q4. [MCQ] [1M] [Easy] Section-A
Select the correct output of the code :
S = "text#next"
print(S.strip("t"))
(A) ext#nex
(B) ex#nex
(C) text#nex
(D) ext#next

Q5. [MCQ] [1M] [Easy] Section-A
Consider the statements given below and then choose the correct output from the given options :
Game="World Cup 2023"
print(Game[-6::-1])
(A) CdrW
(B) ce o
(C) puC dlroW
(D) Error

Q6. [MCQ] [1M] [Easy] Section-A
Identify the output of the following code snippet:
text = "PYTHONPROGRAM"
text=text.replace('PY','#')
print(text)
a) #THONPROGRAM
b) ##THON#ROGRAM
c) #THON#ROGRAM
d) #YTHON#ROGRAM

Q7. [MCQ] [1M] [Easy] Section-A
What is the output of the expression?
country='International'
print(country.split("n"))
a) ('I', 'ter', 'atio', 'al')
b) ['I', 'ter', 'atio', 'al']
c) ['I', 'n', 'ter', 'n', 'atio', 'n', 'al']
d) Error

Q8. [Output Prediction] [1M] [Easy] Section-A
What will be the output of the following code snippet?
message= "World Peace"
print(message[-2::-2])

Q9. [Output Prediction] [3M] [Medium] Section-C
Predict the output of the Python code given below :
s="India Growing"
n = len(s)
m=""
for i in range (0, n) :
    if (s[i] >= 'a' and s[i] <= 'm') :
        m = m + s [i].upper()
    elif (s[i] >= 'O' and s[i] <= 'z') :
        m = m +s [i-1]
    elif (s[i].isupper()):
        m = m + s[i].lower()
    else:
        m = m + '@'
print (m)

--- 2025 Board Exam (7 questions | 10 marks) ---

Q1. [MCQ] [1M] [Easy] Section-A
Identify the correct output of the following code snippet:
game="Olympic2024"
print(game.index("C"))
(A) 0
(B) 6
(C) -1
(D) ValueError

Q2. [MCQ] [1M] [Easy] Section-A
Identify the output of the following code segment:
s = "an apple. a toy."
s=s.find('a',2)
print(s)
(A) 0
(B) 1
(C) 3
(D) 'a'

Q3. [MCQ] [1M] [Easy] Section-A
What is the output of the following expression ?
Sports="Paralympic Games"
print (Sports.split("m"))
(A) ['Paraly','m','pic Ga','m','es']
(B) ('Paraly','m','pic Games')
(C) ('Paraly','pic Ga','es')
(D) ['Paraly','pic Ga','es']

Q4. [MCQ] [1M] [Easy] Section-A
What will be the output of the following Python code?
str= "Soft Skills"
print(str[-3::-3])
a) lSf
b) Stkl
c) StKi
d) l

Q5. [MCQ] [1M] [Easy] Section-A
What is the output of the given Python code?
st='Waterskiing is thrilling!'
print(st.split("i"))
a) ['Watersk', 'ng ', 's thr', 'll', 'ng!']
b) ['Watersk', '', 'ng ', 's thr', 'll', 'ng!']
c) ['Watersk', 'i', 'ng ', 's thr', 'll', 'ng!']
d) Error

Q6. [Output Prediction] [2M] [Easy] Section-B
B. Predict the output of the following Python code:
text="Learn Python with fun and practice"
print(text.partition("with"))
print(text.count("a"))

Q7. [Output Prediction] [3M] [Medium] Section-C
A. Predict the output of the following Python code:
s1="SQP-25"
s2=""
i=0
while i<len(s1):
    if s1[i]>='0' and s1[i]<='9':
        Num=int(s1[i])
        Num-=1
        s2=s2+str(Num)
    elif s1[i]>='A' and s1[i]<='Z':
        s2=s2+s1[i+1]
    else:
        s2=s2+'^'
    i+=1
print(s2)

--- 2026 Board Exam (2 questions | 2 marks) ---

Q1. [MCQ] [1M] [Easy] Section-A
Identify the output of the following code snippet :
s = "the Truth"
print(s.capitalize())
(A) The truth
(B) THE TRUTH
(C) The Truth
(D) the Truth

Q2. [Output Prediction] [1M] [Easy] Section-A
What will be the output of the following statement ?
print("PythonProgram"[-1:2:-2])

===========================================
===========================================
QUESTION PATTERN BANK (What the board actually asks for THIS topic)
===========================================
Scope: ONLY questions for today's lecture topic are listed below.
DO NOT import questions from other topics or chapters.
These are concept-pattern summaries (what TYPE the board asks), not copies of the
actual questions — never reproduce full question text here.

### Concept: String operations
  Pattern: MCQ=20, Output Prediction=6, Short Answer=2 | Marks: 1M=24, 2M=1, 3M=3 | Total: 28 questions
  [MCQ] [1M] [Easy] × 3
    → Core concept of String operations
  [MCQ] [1M] [Easy] × 17
    → Output/result interpretation for the current concept
  [Output Prediction] [3M] [Medium] × 3
    → Output/result interpretation for the current concept
  [Short Answer] [1M] [Easy] × 2
    → True/False: core concept of String operations
  [Output Prediction] [1M] [Easy] × 2
    → Output/result interpretation for the current concept
  [Output Prediction] [2M] [Easy]
    → Output/result interpretation for the current concept


===========================================
===========================================
IMPORTANCE ANALYSIS (allocate teaching time by this ranking)
===========================================
| Rank | Concept | Score | Times Tested | Total Marks | Recent Years | Priority |
|------|---------|-------|-------------|-------------|--------------|----------|
| 1 | String operations | 112 | 28 | 35M | 2026, 2025, 2024 | CRITICAL |

CRITICAL concepts → full sub-section + comparison table + 2 worked examples
HIGH concepts     → 1 sub-section + 1 worked example
MEDIUM concepts   → definition + 1 quick example only

===========================================
EXAMINER FINGERPRINT — TRAPS TO COVER INTERNALLY
===========================================

Use the exam-frequency input only for internal analysis. Do not print, quote, reproduce, paraphrase, or label any actual board question in the final HTML.

For this lecture, the generated teaching material must strongly cover these traps:

No static trap list exists yet for "String operations". Self-generate 4–7 traps from:
- actual question patterns for String operations
- common wrong assumptions students make about this concept
- output-tracing traps
- syntax-vs-runtime traps
- comparison traps
- order/sequence traps

Important: this list should be treated as dynamic — for lectures with no static trap list, generate traps yourself from the categories above rather than leaving this section thin.
===========================================
YOUR TASK — Generate a complete classroom-ready teaching package
===========================================

Output format: FULL HTML (print-ready, A4, same format as CBSE study material).
Use the CSS classes below. NO plain Markdown — use HTML elements only.

HTML STRUCTURE TO GENERATE:

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width,initial-scale=1">
<title>String operations Theory — Lecture 8</title>
<style>
/* ── PRINT SETUP ── */
@page { size: A4; margin: 12mm 14mm 12mm 14mm; }
* { box-sizing: border-box; }

/* ── BASE ── */
body { font-family: 'Segoe UI', Arial, sans-serif; font-size: 9.5pt; color: #1a1a2e; line-height: 1.4; background: #fff; margin: 0; padding: 0; }

/* ── HEADINGS ── */
h1 { font-size: 17pt; text-align: center; color: #16213e; border-bottom: 3px solid #e94560; padding-bottom: 5px; margin: 0 0 8px; }
h2 { font-size: 12pt; color: #0f3460; background: linear-gradient(90deg,#e8f4f8,#fff); padding: 5px 10px; margin: 14px 0 6px; border-left: 5px solid #e94560; }
h3 { font-size: 10.5pt; color: #16213e; border-bottom: 1.5px dashed #ccc; padding-bottom: 3px; margin: 10px 0 4px; }

/* ── CONTENT BOXES ── */
.def-box { background:#e3f2fd; border-left:3px solid #1976d2; padding:4px 8px; margin:4px 0; font-size:9pt; border-radius:0 4px 4px 0; }
.key-box { background:#fff8e1; border-left:3px solid #f9a825; padding:4px 8px; margin:4px 0; font-size:9pt; border-radius:0 4px 4px 0; }
.key-box ul { margin:3px 0 0 12px; padding:0; }
.key-box li { margin:2px 0; }
.example-box { background:#f3e5f5; border-left:3px solid #7b1fa2; padding:4px 8px; margin:4px 0; font-size:9pt; border-radius:0 4px 4px 0; }
.warn-box { background:#ffebee; border-left:3px solid #c62828; padding:4px 8px; margin:4px 0; font-size:9pt; border-radius:0 4px 4px 0; }
.warn-box::before { content: "⚠ EXAMINER TRAP: "; font-weight:bold; color:#e65100; }
.tip-box { background:#e8f5e9; border-left:3px solid #2e7d32; padding:4px 8px; margin:4px 0; font-size:9pt; border-radius:0 4px 4px 0; }
.recall-box { background:#e8f5e9; border-left:3px solid #2e7d32; padding:4px 8px; margin:4px 0; font-size:9pt; font-weight:bold; border-radius:0 4px 4px 0; }

.mcq-box { background:#f8f9fa; border:1px solid #dee2e6; padding:6px 10px; margin:5px 0; border-radius:4px; font-size:9pt; }
.options { list-style:none; margin:4px 0 0 0; padding:0; }
.options li { padding:2px 0; }
.options li.wrong { color:#c62828; }
.options li.correct { color:#2e7d32; font-weight:bold; }
.options .why { font-size:8pt; color:#555; margin-left:8px; font-style:italic; }
.self-test-box { background:#e8eaf6; border:1px dashed #5c6bc0; padding:6px 10px; margin:6px 0; border-radius:4px; font-size:9pt; }
details summary {
  cursor:pointer; display:inline-block; margin-top:6px; padding:2px 10px;
  background:#e8eaf6; color:#3949ab; border:1px solid #9fa8da;
  border-radius:4px; font-size:8.5pt; font-weight:600; user-select:none;
  list-style:none;
}
details summary::-webkit-details-marker { display:none; }
details[open] > summary { background:#c5cae9; }
details > *:not(summary) { margin-top:6px; }

/* ── CODE ── */
pre {
  background:#f8f9fa;
  color:#212529;
  border:1px solid #dee2e6;
  border-radius:4px;
  margin:4px 0;
  padding:8px 10px;
  font-size:8.5pt;
  line-height:1.5;
  white-space:pre-wrap;
  word-break:break-word;
}
pre code {
  white-space:pre;
  word-break:normal;
  display:block;
  overflow-x:auto;
  font-size:inherit;
}
code {
  font-family:'Courier New', monospace;
  font-size:0.95em;
}
.kw { color:#0000ff; } .bi { color:#267f99; } .st { color:#a31515; }
.cm { color:#008000; } .nm { color:#098658; } .fn { color:#795e26; }
.va { color:#001080; }

/* ── TABLES ── */
table { border-collapse:collapse; width:100%; margin:5px 0; font-size:8.5pt; }
th, td { border:1px solid #bbb; padding:3px 6px; text-align:left; }
th { background:#eeeeee; font-weight:bold; color:#333; }
tr:nth-child(even) { background:#fafafa; }
.highlight-row { background:#fff9c4 !important; font-weight:bold; }

/* ── CARDS ── */
.card-grid { display:grid; grid-template-columns:repeat(auto-fit,minmax(200px,1fr)); gap:6px; margin:8px 0; }
.card { background:#fff; border:1px solid #ccc; border-radius:4px; padding:6px 8px; font-size:8.5pt; }
.card .card-title { font-weight:bold; font-size:9pt; color:#0f3460; margin-bottom:3px; border-bottom:1px solid #eee; padding-bottom:2px; }

/* ── PRIORITY TAGS ── */
.priority-tag { font-size:7.5pt; padding:1px 6px; border-radius:10px; font-weight:bold; white-space:nowrap; }
.critical { background:#fce4ec; color:#ad1457; }
.high { background:#fff3e0; color:#e65100; }
.medium { background:#fff8e1; color:#f57f17; }
.marks-badge { display:inline-block; background:#e94560; color:#fff; font-size:7.5pt; padding:1px 5px; border-radius:10px; font-weight:bold; margin-left:5px; }

/* ── TOC STICKY SIDEBAR (screen only) ── */
@media screen {
  body { display:grid; grid-template-columns:165px 1fr; gap:0; }
  .toc-sidebar { position:sticky; top:0; height:100vh; overflow-y:auto; background:#f8f9fa; padding:10px 6px; font-size:8pt; color:#333; border-right:1px solid #ddd; }
  .toc-sidebar h4 { font-size:8.5pt; color:#16213e; margin:0 0 8px; padding-bottom:4px; border-bottom:1px solid #ddd; }
  .toc-sidebar a { display:block; color:#0f3460; text-decoration:none; padding:2px 4px; border-radius:3px; margin-bottom:1px; }
  .toc-sidebar a:hover { background:#e8f4f8; }
  .toc-sidebar .toc-h3 { padding-left:10px; font-size:7.5pt; color:#555; }
  .main-content { padding:10px 14px; min-width:0; }
}
@media screen and (max-width:640px) {
  body { grid-template-columns:1fr; }
  .toc-sidebar { display:none; }
  .main-content { grid-column:1 / -1; padding:8px; }
}
@media print {
  .toc-sidebar { display:none; }
  .main-content { grid-column:1 / -1; padding:0; }
  body { display:block; }
  .print-bar { display:none; }
  .collapse-btn { display:none !important; }
  .section-body { display:block !important; }
  /* Force all <details> open and hide the toggle-button summary text */
  details { display:block !important; }
  details > *:not(summary) { display:block !important; visibility:visible !important; }
  details > summary { display:none !important; }
}

/* ── PRINT BUTTONS ── */
.print-bar { position:fixed; top:8px; right:8px; display:flex; gap:6px; z-index:999; }
.print-btn { padding:5px 14px; color:#fff; border:none; border-radius:4px; cursor:pointer; font-size:9pt; box-shadow:0 2px 6px rgba(0,0,0,0.3); }
.print-btn.color-btn { background:#e94560; }
.print-btn.bw-btn { background:#333; }
.print-btn.back-btn { background:#1976d2; display:none; }
.print-btn.read-btn { background:#2e7d32; }

/* ── READ MODE ── */
@media screen {
  body.read-mode .print-bar { display:none !important; }
  body.read-mode .toc-sidebar { display:none !important; }
  body.read-mode .main-content {
    grid-column:1 / -1; max-width:860px; margin:0 auto;
    padding:24px 32px; font-size:11pt; line-height:1.75;
  }
}
#btnExitRead {
  display:none; position:fixed; bottom:16px; right:16px;
  background:rgba(0,0,0,0.55); color:#fff; border:none; border-radius:20px;
  padding:6px 14px; font-size:9pt; cursor:pointer; z-index:9999;
}
body.read-mode #btnExitRead { display:block; }
@media print { #btnExitRead { display:none !important; } }

/* ── B&W MODE OVERRIDES ── */
body.bw-mode { background:#fff !important; color:#000 !important; }
body.bw-mode .def-box, body.bw-mode .key-box, body.bw-mode .example-box,
body.bw-mode .warn-box, body.bw-mode .tip-box, body.bw-mode .recall-box,
body.bw-mode .mcq-box, body.bw-mode .self-test-box {
  background:#fff !important; border:1px solid #ccc !important; border-left:none !important;
}
body.bw-mode h1 { color:#000 !important; border-bottom:2px solid #000 !important; }
body.bw-mode h2 { background:#fff !important; border-left:2px solid #000 !important; color:#000 !important; }
body.bw-mode h3 { color:#000 !important; border-bottom:1px solid #000 !important; }
body.bw-mode pre { background:#fff !important; color:#000 !important; border:1px solid #ccc !important; }
body.bw-mode .kw, body.bw-mode .bi, body.bw-mode .st, body.bw-mode .cm,
body.bw-mode .nm, body.bw-mode .fn, body.bw-mode .va { color:#000 !important; }
body.bw-mode table th { background:#eee !important; color:#000 !important; }
body.bw-mode tr:nth-child(even) { background:#fff !important; }
body.bw-mode .priority-tag, body.bw-mode .marks-badge { background:#fff !important; color:#000 !important; border:1px solid #000 !important; }
body.bw-mode .card { background:#fff !important; border:1px solid #ccc !important; }
body.bw-mode .highlight-row { background:#fff !important; }
body.bw-mode .toc-sidebar { background:#fff !important; border-right:1px solid #ccc !important; }
body.bw-mode .toc-sidebar a { color:#000 !important; }

/* ── COLLAPSIBLE SECTIONS ── */
.collapse-btn { float:right; background:none; border:none; cursor:pointer; font-size:10pt; color:#aaa; padding:0 4px; margin-left:6px; }
.collapse-btn:hover { color:#e94560; }
</style>
</head>
<body>

<!-- Print / mode buttons (hidden on print) -->
<div class="print-bar">
  <button class="print-btn read-btn"   id="btnReadMode" onclick="toggleReadMode()">&#128214; Read Mode</button>
  <button class="print-btn back-btn"   id="btnBackColor" onclick="backToColor()">&#127775; Back to Color</button>
  <button class="print-btn bw-btn"     id="btnPrintBW"   onclick="printBW()">&#128438; Print B&amp;W</button>
  <button class="print-btn color-btn"                    onclick="printColor()">&#128438; Print Color</button>
</div>
<button id="btnExitRead" onclick="toggleReadMode()">&#10005; Exit Read Mode</button>

<!-- JS: print modes + collapsible sections + TOC auto-build -->
<script>
function printColor() {
  document.body.classList.remove('bw-mode');
  document.getElementById('btnPrintBW').style.display='inline-block';
  document.getElementById('btnBackColor').style.display='none';
  window.print();
}
function printBW() {
  document.body.classList.add('bw-mode');
  document.getElementById('btnPrintBW').style.display='none';
  document.getElementById('btnBackColor').style.display='inline-block';
  window.print();
}
function backToColor() {
  document.body.classList.remove('bw-mode');
  document.getElementById('btnPrintBW').style.display='inline-block';
  document.getElementById('btnBackColor').style.display='none';
}
function toggleReadMode() {
  document.body.classList.toggle('read-mode');
}

// Auto-collapsible h2/h3 sections
(function(){
  function setup(){
    document.querySelectorAll('.main-content h2,.main-content h3').forEach(function(h){
      var btn=document.createElement('button');
      btn.className='collapse-btn';btn.textContent='▼';
      h.appendChild(btn);
      var wrapper=document.createElement('div');wrapper.className='section-body';
      var level=parseInt(h.tagName[1]),next=h.nextElementSibling;
      while(next){
        var tag=next.tagName||'';
        if(/^H[1-6]$/.test(tag)&&parseInt(tag[1])<=level)break;
        var after=next.nextElementSibling;wrapper.appendChild(next);next=after;
      }
      h.insertAdjacentElement('afterend',wrapper);
      btn.addEventListener('click',function(e){
        e.stopPropagation();
        var open=wrapper.style.display!=='none';
        wrapper.style.display=open?'none':'';
        btn.textContent=open?'▶':'▼';
      });
    });
    // Expand/Collapse All in TOC
    var toc=document.querySelector('.toc-sidebar');
    if(toc){
      var bar=document.createElement('div');
      bar.style.cssText='display:flex;gap:4px;margin-bottom:8px;';
      ['Expand All','Collapse All'].forEach(function(label){
        var b=document.createElement('button');
        b.textContent=label;
        b.style.cssText='flex:1;font-size:7.5pt;padding:2px 4px;border:1px solid #ccc;border-radius:3px;cursor:pointer;background:#fff;';
        b.addEventListener('click',function(){
          var expand=label==='Expand All';
          document.querySelectorAll('.section-body').forEach(function(w){w.style.display=expand?'':'none';});
          document.querySelectorAll('.collapse-btn').forEach(function(b){b.textContent=expand?'▼':'▶';});
        });
        bar.appendChild(b);
      });
      toc.insertBefore(bar,toc.firstChild);
    }
    // Auto-build TOC links from h2/h3 IDs
    if(toc){
      document.querySelectorAll('.main-content h2,.main-content h3').forEach(function(h){
        if(!h.id){h.id=h.textContent.trim().replace(/[^a-z0-9]+/gi,'-').toLowerCase().slice(0,40);}
        var a=document.createElement('a');
        a.href='#'+h.id;
        a.textContent=h.textContent.replace('▼','').replace('▶','').trim();
        if(h.tagName==='H3')a.classList.add('toc-h3');
        toc.appendChild(a);
      });
    }
  }
  if(document.readyState==='loading'){document.addEventListener('DOMContentLoaded',setup);}else{setup();}
})();

// Auto-open details when printing
(function(){
  function openDetails(){
    document.querySelectorAll('details').forEach(function(d){
      if(!d.hasAttribute('open')){d.setAttribute('data-was-closed','');d.setAttribute('open','');}
    });
    document.querySelectorAll('.section-body').forEach(function(w){
      if(w.style.display==='none'){w.setAttribute('data-was-hidden','');w.style.display='';}
    });
  }
  function restoreDetails(){
    document.querySelectorAll('[data-was-closed]').forEach(function(d){d.removeAttribute('open');d.removeAttribute('data-was-closed');});
    document.querySelectorAll('[data-was-hidden]').forEach(function(w){w.style.display='none';w.removeAttribute('data-was-hidden');});
  }
  window.addEventListener('beforeprint',openDetails);
  window.addEventListener('afterprint',restoreDetails);
})();
</script>

<!-- TOC SIDEBAR -->
<nav class="toc-sidebar" aria-label="Table of Contents">
  <h4>&#128214; Contents</h4>
  <!-- TOC links auto-built by JS above -->
</nav>

<!-- MAIN CONTENT -->
<div class="main-content">

Generate these sections in order (all inside the main-content div):

<h1 id="top">String operations Theory — Lecture 8</h1>
<p style="text-align:center;color:#555;font-size:8.5pt;">CBSE | XII CS | Computational Thinking and Programming – 2 | 35 min</p>

<h2 id="s1">1. Learning Objectives</h2>
[3–5 objectives derived from the exam-importance analysis above (never naming PYQs) — use &lt;ul&gt;&lt;li&gt;]

<h2 id="s2">2. 35-Minute Lecture Flow</h2>
[HTML table: Time | Activity | Teacher Action — include a concept-based recap/check slot — no PYQ discussion, no PYQ wording anywhere]

<h2 id="s3">3. Concept Notes</h2>
[For EVERY sub-concept surfaced by the exam-frequency analysis, never naming or displaying actual board questions:
  - .def-box for definition with "In exam language: ..." line
  - .key-box with syntax/rules as &lt;ul&gt;&lt;li&gt;
  - .example-box for worked examples
  - &lt;pre&gt;&lt;code&gt; for code with .kw/.bi/.st/.cm/.nm token spans
  - .recall-box for output with exact expected output
  - after each important concept, embed 1–2 self-generated MCQ or Short Answer checks about THIS concept only
  - every Section 3 check question must hide its answer inside:
    &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;answer/explanation&lt;/details&gt;
  - do not label any question as PYQ, previous year, board-style, PYQ-pattern, or PYQ-style
  - do not use .pyq-box or .pyq-meta here (in Combined mode .pyq-box is reserved for Section 7)
]

<h2 id="s4">4. Examiner Tricks &amp; Common Mistakes</h2>
[Create one .warn-box for each trap from the EXAMINER FINGERPRINT section.
Each .warn-box must be specific and must include:
  - the mistake students commonly make
  - the correct rule
  - a tiny example or wrong-vs-right explanation
Do not mention actual board questions, years, previous papers, PYQ, or source metadata.]

<h2 id="s5">5. Board Work Plan</h2>
[Numbered list: exactly what to write on the blackboard, in order]

<h2 id="s6">6. Classroom Practice Questions</h2>
[Self-generated from the examiner-trap patterns analysed above — never call these PYQ-pattern/PYQ-style/board-style. CRITICAL: every answer MUST be inside &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;...&lt;/details&gt; — never expose the answer directly.

3×1M MCQ + 5×1-2M Short Answer only.
Theory lecture restriction:
- Do NOT include actual PYQs.
- Do NOT include programming/long-answer/HOTS questions in theory lecture practice.
- Frame original MCQ/Short Answer questions from exam-frequency concepts and examiner traps only.
- Every question must map to one concept/trap discovered in Section 4.

MCQ structure:
&lt;div class="mcq-box"&gt;
  &lt;b&gt;Q1.&lt;/b&gt; Question text?&lt;br&gt;
  &lt;ul class="options"&gt;
    &lt;li&gt;a) ...&lt;/li&gt;
    &lt;li&gt;b) ...&lt;/li&gt;
    &lt;li&gt;c) ...&lt;/li&gt;
    &lt;li&gt;d) ...&lt;/li&gt;
  &lt;/ul&gt;
  &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;
    &lt;ul class="options"&gt;
      &lt;li class="wrong"&gt;a) ... — reason why wrong&lt;/li&gt;
      &lt;li class="correct"&gt;b) ... ✓ — reason why correct&lt;/li&gt;
      ...
    &lt;/ul&gt;
  &lt;/details&gt;
&lt;/div&gt;

Short-answer structure:
&lt;div class="self-test-box"&gt;&lt;b&gt;Q4.&lt;/b&gt; Question&lt;br&gt;&lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;Full answer&lt;/details&gt;&lt;/div&gt;]



<h2 id="s7">7. Student Notes (Copy-ready)</h2>
[Concise notes — every concept highlighted by the exam-frequency analysis, written purely as concept notes (no PYQ wording) — in .key-box and .def-box; self-check questions in .self-test-box with &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;answer&lt;/details&gt;]

<h2 id="s8">8. Homework</h2>
[DYNAMIC HOMEWORK — match this concept and the question types the board actually uses for it
(self-generate the questions; never label them as previous-year or board questions):
- 2×1M (MCQ / very-short answer)
- 2×2M short answer
- 1×3M short answer (or, for a coding topic, a short program / output-prediction question)
- You MAY include one 3–5M long-answer or programming question (this concept supports it)
Dynamic rule: include a 5M long-answer or a programming question ONLY when this concept is genuinely
assessed that way; never force unsupported marks (e.g. a 5M) or question types. same concept — self-generated, never labelled as PYQ-pattern or board-style.
Mark difficulty with .critical/.high/.medium tag.
EVERY answer wrapped in &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;...&lt;/details&gt; inside .self-test-box or .mcq-box]

<h2 id="s9">9. Exam Tips</h2>
[5 specific tips as .tip-box — derived from examiner traps for THIS topic only — written as plain tips, no PYQ wording]

<h2 id="s10">10. Last-Minute Revision Cards</h2>
&lt;div class="card-grid"&gt;
[One .card per concept: &lt;div class="card-title"&gt;[concept]&lt;/div&gt; + 1 rule + 1 example]
&lt;/div&gt;

</div><!-- end .main-content -->
</body>
</html>

HARD OUTPUT RULES:
- Output ONLY the HTML document starting with &lt;!DOCTYPE html&gt;
- Do NOT wrap the output in markdown code fences.
- Do NOT add explanatory text before or after the HTML.
- Use ONLY content from the lecture topic ("String operations").
- Do NOT include content from other topics.
- The exam-frequency input is private analysis only.
- Final visible HTML must NOT include:
    * actual board question text
    * year labels
    * section labels from papers
    * previous-paper metadata
    * the word "PYQ"
    * phrases like "previous year question", "PYQ-style", "PYQ-pattern", or "board-style"
- Every question, example, and practice item in the final HTML must be self-generated and concept-focused.
- Always finish the document completely through &lt;/html&gt;.
- If the answer becomes long, keep Section 3 complete first, then make Sections 7–10 compact instead of truncating.
- However many concepts the analysis surfaces, self-generate enough Section 3 and Section 6 checks to cover all important traps.
- Never dump real board questions to compensate for a large question pool.

ANSWER HIDING RULES:
- Section 3 concept checks: every answer must be hidden inside &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;...&lt;/details&gt;.
- Section 6 MCQs: options must be listed without .correct or .wrong before details.
- Section 6 MCQ answer analysis must appear only inside &lt;details&gt;.
- Section 6 short-answer questions: every answer must be hidden inside &lt;details&gt;.
- Section 7 self-check questions: every answer must be hidden inside &lt;details&gt;.
- Section 8 homework: every answer must be hidden inside &lt;details&gt;.
- The beforeprint JS already auto-opens all &lt;details&gt; for printing; never remove or skip this feature.

THEORY LECTURE STRUCTURE RULE:
- This theory lecture has no visible board-question discussion section.
- Sections 7–10 are allowed and required:
    Section 7: Student Notes
    Section 8: Homework
    Section 9: Exam Tips
    Section 10: Last-Minute Revision Cards

CODE SIZE RULE:
- Inline code must appear almost the same size as surrounding normal text.
- Do NOT use fixed 8.5pt size for all &lt;code&gt; elements.
- Use code { font-size:0.95em; } for inline code.
- Use pre { font-size:8.5pt; } for block code.
- Use pre code { font-size:inherit; } so code blocks remain compact.
- Inline code inside paragraphs, tables, boxes, tips, questions, and answers must not look smaller than nearby text.

BOX / CLASS USAGE RULES:
- Do NOT use .pyq-box or .pyq-meta in theory lectures.
- Use .mcq-box for MCQs.
- Use .self-test-box for short-answer checks and homework.
- Use .warn-box for examiner traps.
- Use .tip-box for exam tips.
- Use .def-box and .key-box for notes.
- Use .example-box for worked examples.
- Use .recall-box for exact output.

HTML TEMPLATE RULES:
- All generated content must go inside &lt;div class="main-content"&gt;.
- The &lt;nav class="toc-sidebar"&gt; is already present in the template.
- JS auto-builds TOC links from h2/h3 headings.
- Print buttons including Read Mode are already present in the template.
- Do NOT add print buttons again.
- Include the full CSS and JS exactly as given.

# ENHANCED PPT GENERATION PROMPT
## Topic: String operations Theory | CBSE XII CS Computer Science

================================================
SECTION A -- VISUAL IDENTITY (READ FIRST, APPLY TO EVERY SLIDE)
================================================

COLOUR PALETTE -- "Deep Code" Theme
  Role              Hex        Name             Where Used
  Primary (dark)    #0D1B2A    Midnight Navy    Title bg, conclusion bg
  Secondary         #1B4F72    Ocean Blue       Section header cards, accent shapes
  Accent            #00D4FF    Cyan Electric    Keywords, callout borders, badges
  Neutral light     #F0F4F8    Ice White        All content slide backgrounds
  Warning/Error     #E74C3C    Alert Red        Common mistakes slide, warnings
  Success/Tip       #27AE60    Emerald Green    Tips, correct syntax, exam tips
  Text primary      #1A1A2E    Near Black       Body text on light slides
  Text on dark      #FFFFFF    Pure White       All text on dark background slides
  Text muted (dark) #C9D4E0    Slate Mist       Sub-lines / captions on navy slides

ON-LIGHT VARIANTS (use for ANY text, keyword, icon, or thin border on Ice White):
  Cyan  -> Accent-Deep  #0077A3      Emerald -> #1E8449      Red -> #C0392B
CONTRAST RULE: bright Cyan #00D4FF / Emerald #27AE60 / Red #E74C3C are for DARK
backgrounds or thick (>=4 pt) shape fills ONLY -- never for thin text, borders, or
badges on a light slide (bright cyan on Ice White is ~1.6:1 contrast = invisible
from the back row). On light slides always use the deep variants above.

COLOUR DISCIPLINE -- 60 / 30 / 10 (this is what separates "designed" from "filled-in")
  * 60% of every content slide is the Ice White background + generous EMPTY space.
    Empty space is a design element, not a slide you failed to fill.
  * 30% is ONE neutral structural element -- a single card, panel, or diagram.
  * 10% -- and NO MORE -- is the accent (Cyan Electric or one status colour). One
    accent MOMENT per slide: the focal chip, the keyword, the one arrow that
    matters. A slide where every box is coloured has NO accent -- it is noise.
  * Build depth with TINTS of one hue, never many saturated hues. A card fill is a
    6-8% tint of its header colour (pale-blue body under an Ocean Blue header),
    never a strong fill behind text. Status tints: blue 6% = definition,
    green 6% = correct/tip, red 6% = wrong/trap. Borders are 1 pt in the deep
    variant -- not thick coloured frames.
  * Navy dominates ONLY the Title and Key Takeaways slides. Never split a content
    slide 50/50 navy-vs-white -- it destroys hierarchy.

GRID & COMPOSITION (the missing rule that makes slides look intentional)
  * Lay every content slide on a 12-column grid inside the safe area with a
    consistent ~0.2 inch gutter. Snap every card, text block, icon and diagram
    edge to a column line -- never free-float objects at arbitrary x positions.
  * ONE alignment spine per slide: a single left text column (Left Icon+Text),
    two balanced 6-column halves (Two Column), or one centred focal object
    (Callout / Exam Spotlight). Do not mix three alignments on one slide.
  * Align tops and left edges across objects. Ragged, slightly-off edges are the
    #1 reason a slide reads as amateur even when nothing technically overlaps.

VISUAL HIERARCHY -- ONE FOCAL POINT PER SLIDE
  * Every slide answers "what is the ONE thing the eye lands on first?" Make that
    element the largest / boldest / the only accent-coloured object; everything
    else is visibly secondary (smaller, neutral, lighter).
  * Hierarchy comes from SCALE CONTRAST and SPACE, not from boxing everything. A
    big number, one code line, or a single diagram surrounded by white beats
    three equal-weight bordered boxes every time.
  * Reserve bold + accent colour for the focal point ONLY. If three things are
    bold and coloured, nothing is emphasised.

INFORMATION-CARRYING VISUALS (the default -- not decorative chrome)
  * The visual must MEAN something: it carries the concept, it is not an ornament
    around text. Prefer, in order: a labelled code-breakdown (one code line on a
    dark card with arrows naming each part's role), a before/after, a flow
    (input -> process -> output), a comparison table, a decision tree.
  * A rounded box with a clip-art icon beside a bullet is chrome -- it explains
    nothing and should be cut. One strong visual that teaches the idea beats four
    small decorative ones.
  * Icons: line-style, ONE consistent family, used to label SECTIONS only -- not
    one circle per bullet. An icon on every line is clutter, not design.

TYPOGRAPHY -- CLASSROOM-OPTIMISED (NON-NEGOTIABLE)
  Element             Font              Size   Weight    Notes
  Slide title         Montserrat        44 pt  Bold      Visible from back row (Arial Bold if Montserrat unavailable)
  Focal number/word   Montserrat        60+ pt Bold      The one hero element may go large for scale contrast
  Section header      Arial             32 pt  Bold      Sub-headings inside slides
  Body bullets        Calibri           28 pt  Regular   MAX 3 bullets -- min 28 pt
  Code text           Courier New       24 pt  Regular   On dark card only
  Captions/labels     Calibri           24 pt  Italic    Footer only; keep non-essential and brief

  NEVER go below 24 pt for ANY visible text.
  NEVER use Aptos, Thin fonts, or Calibri Light.
  Line spacing 1.15+. Title case for titles; sentence case for body.

VISUAL MOTIF -- "Bracket Accent" (restrained signature, not the main visual)
  * Small { } mark (Cyan Electric on dark / Accent-Deep #0077A3 on light) sits
    quietly top-left of the title -- a signature, never a slide's main visual.
  * Definitions: a single rounded callout with a 4 pt Cyan-Electric LEFT border
    only (no full frame). Code: dark #0D1B2A card, #00D4FF keywords, white rest.

DESIGN NEVER-DO LIST
  NO accent lines below titles
  NO colour bars or stripes spanning full slide width
  NO vertical sidebar stripes
  NO cream/beige backgrounds
  NO saturated colour fills behind body text (use 6-8% tints instead)
  NO icon-circle on every bullet, no clip-art decoration
  NO three competing focal points -- exactly one hero element per slide
  NO evenly-tiled grid of identical boxes whose only job is to fill the slide
  NO text-only slides -- every slide needs ONE information-carrying visual
  NO centred body text -- left-align all bullets
  NO more than 3 bullets per slide
  NO bullet longer than 10 words
  NO font below 24 pt

LAYOUT VARIETY -- ROTATE WHEN IT HELPS CLARITY
  Layout Name         When to Use
  Full-bleed Dark     Title slide, Key Takeaways slide
  Left Icon+Text      Theory slides -- icon circle left, bullets right
  Two Column          Comparisons (list vs tuple, == vs is, mutable vs immutable, etc.)
  Code Card           All code examples -- dark card on light background
  Callout Box         Definitions -- rounded rect, Cyan Electric border
  Exam Spotlight      Concept Practice slides -- large question centred on card
  3-Icon Grid         Key Takeaways -- 3 icons in equal columns
  Warning Banner      Common Mistakes -- red accent, alert icon

================================================
SECTION A1 -- LAYOUT SAFETY & OVERLAP PREVENTION
================================================

NON-NEGOTIABLE SAFE ZONE RULES:
  * Every slide must use a fixed 16:9 widescreen canvas.
  * Keep a minimum 0.35 inch margin from all slide edges.
  * No text box, badge, icon, card, or diagram may overlap another object.
  * Title area must be reserved separately from body area.
  * Body content must start only after the title area ends.

TITLE SAFE AREA:
  * Slide title box position: top 0.35 inch to 1.15 inch only.
  * No badge, icon, card, or body text may enter this title zone.
  * If title is long, wrap into maximum 2 lines.
  * Never allow title text to touch badges or cards.

BADGE PLACEMENT RULE:
  * Badges such as "Quick Recap", "Practice Question", "1M", "60 seconds" must be placed
    in a fixed safe badge zone.
  * Badge zone: top-right corner, x >= 10.0 inch, y between 0.35 and 0.85 inch.
  * Badge must never be placed near the centre title area.
  * Badge text must stay inside the badge shape with 0.08 inch internal padding.

BODY SAFE AREA:
  * Body content must begin at y >= 1.45 inch on every content slide.
  * Large cards/callouts must begin at y >= 1.55 inch.
  * Bottom footer/caption area starts at y >= 6.85 inch.
  * Do not place main content in the footer zone.

TEXT FITTING RULE:
  * Do NOT shrink font below the required size.
  * If content does not fit, split into a continuation slide.
  * Use "(contd...)" in the title for continuation slides.
  * Never use PowerPoint auto-fit that reduces font size.
  * Never compress line spacing below 1.05.

OBJECT COLLISION CHECK -- before finalising each slide, verify:
  [ ] Title does not overlap badge.
  [ ] Badge does not overlap title or body.
  [ ] Body text does not overlap cards or icons.
  [ ] Code card has enough internal padding.
  [ ] No object is outside slide boundary.
  [ ] All text is fully visible after rendering.

RENDER QUALITY CHECK:
  After creating the PPT, render every slide as an image and inspect all
  rendered slides visually. If any slide has overlapping, clipped, hidden, or
  tiny text: fix the layout, split the slide if needed, render again, and only
  then provide the final PPT.

STRICT FAILURE RULE:
  A slide with overlapping text, clipped title, hidden badge, or unreadable
  content is considered FAILED and must be rebuilt before delivery.

================================================
SECTION B -- CONTENT SPECIFICATION
================================================

Topic     : String operations Theory
Lecture   : #8 | Target duration: 35 min | Board: CBSE
Chapter   : Computational Thinking and Programming – 2
Class     : XII CS | Subject: Computer Science
Audience  : Class XII, CBSE Board, average to above-average students preparing for board exams

STRICT RULE: Every slide must be about "String operations Theory" ONLY.

GENERATED STUDY NOTES HTML INPUT (OPTIONAL BUT PREFERRED):
  If the user provides/pastes the generated HTML study notes file for this lecture,
  treat that HTML as the AUTHORITATIVE theory source for the deck.
  Summarise all concepts from the HTML into slide-friendly bullets, examples,
  diagrams, tables, and speaker notes. Do NOT copy long HTML paragraphs verbatim.
  Theory/content slides come from the HTML study notes.
  Concept Practice slides are self-generated using Section F's Concept Practice Rule.

DECK GOAL: This deck is the polished, exam-focused version of the study notes —
NOT a list of definitions. Teach what the examiner actually tests. Lead with the
CRITICAL & CONFUSING concepts flagged in Section F (EXAM FOCUS -- private analysis input,
never printed), give them the most slide time, disambiguate every look-alike pair, and
surface self-generated practice questions inspired by that analysis (never the real
previous-year questions themselves). Cover every concept the analysis names — drop none
to save slides.

SLIDE COUNT -- DETERMINE BY CONTENT, NOT A FIXED NUMBER:
  Do not compress or stretch the topic to hit a fixed slide count.
  For a single-concept theory lecture, typical deck size is 11-16 slides.
  For multi-concept lectures, typical deck size is 18-30 slides.
  The actual count depends on concept density, examples, traps, and practice needs.
  Never stretch a small topic only to reach 18 slides.
  Never cram a large topic into fewer slides by shrinking fonts or overcrowding.
    * CRITICAL/HIGH subtopics listed in Section D get dedicated slides.
    * MEDIUM subtopics may share a slide unless they have multiple distinct cases.
    * If a subtopic has MULTIPLE DISTINCT CASES (e.g. list, tuple, dictionary and string operations side by side),
      give EACH case its own slide or clearly separated section — never
      compress distinct cases into one bullet list just to save slides.
    * CRITICAL-priority subtopics (Section F) --> 2 slides: theory + worked example.
    * HIGH-priority subtopics --> 1 dedicated slide.
    * MEDIUM-priority subtopics --> 1 bullet on a shared slide, UNLESS that
      subtopic has multiple distinct cases (above), then give it its own slide too.
    * CONTINUATION (encouraged — do NOT cram): when one concept needs more room
      than a single slide allows (more than 3 bullets, or theory + worked example
      + an exam trap), SPLIT it across consecutive slides. Title the overflow slide
      "<SAME TOPIC> (contd...)" and add a small "...continue ->" marker bottom-right
      of the first slide so the flow is obvious. Two clean slides always beat one
      crowded slide — never shrink the font or exceed 3 bullets just to make it fit.
  Fixed-position slides (always present, regardless of total count):
    Title, Agenda, Prior Knowledge Check        -- start of deck
    Common Mistakes                         -- immediately after content slides
    Concept Practice (4 self-generated questions, EASY to TOUGH) -- after Common Mistakes
    Key Takeaways, Exit Ticket              -- final two slides, in that order

EXAMPLE SINGLE-CONCEPT DECK SHAPE (illustrative only -- adapt slide count and
content-slide breakdown to THIS lecture's actual concept, not to this example):
    1. Title
    2. Agenda
    3. Prior Knowledge Check
    4. Concept overview
    5-8. Concept-specific flow/example slides (split the concept into its natural
         sub-steps or look-alike comparisons -- do not force exactly 4)
    9. Common Mistakes
    10-13. Four Concept Practice slides
    14. Key Takeaways
    15. Exit Ticket


EXPLAIN FOR UNDERSTANDING, NOT JUST RECALL (the most important rule here):
  A student must understand the concept by reading the slide ONCE, without
  the teacher's voice filling gaps. For every theory/definition slide:
    * Start with a one-line plain-English restatement ("In simple words: ...")
      -- not just the textbook/jargon definition.
    * Follow with ONE tiny concrete example showing the concept in action
      (nums[-1], len(nums), d.get("a"), a real value, a real before/after) -- never leave
      a definition abstract with no example near it.
    * If two things are easily confused (e.g. mutable list vs immutable tuple, == vs is), show them side by side on a Two Column slide -- never describe
      look-alike concepts on separate, disconnected slides.

================================================
SECTION C -- SLIDE OUTPUT FORMAT (USE EXACTLY)
================================================

+=======================================================+
SLIDE [n]: [SLIDE TITLE IN CAPS]
Layout     : [Full-bleed Dark / Left Icon+Text / Two Column /
              Code Card / Callout Box / Exam Spotlight /
              3-Icon Grid / Warning Banner]
Background : [#0D1B2A or #F0F4F8]
Title font : Montserrat Bold -- 44 pt on body slides / 54 pt on the Title slide
Body font  : Calibri 28 pt Regular
-------------------------------------------------------
VISUAL ELEMENT: [icon/shape/code card/diagram on this slide]

[Bullet 1 -- max 10 words]  (blue circle = definition)
[Bullet 2 -- max 10 words]  (green circle = tip)
[Bullet 3 -- max 10 words]  (red circle = warning)

CODE SLIDES -- paste inside dark card:
  +------------------------------------------+
  |  nums = [10, 20, 30]                      |
  |  print(nums[-1], len(nums))   # 30 3     |
  |  d = {"a": 1}; d["b"] = 2                 |
  |  print(d.get("a"), "b" in d)  # 1 True   |
  +------------------------------------------+
  OUTPUT: 30 3
          1 True

DIAGRAM SLIDES: describe shapes, arrows, labels, layout
-------------------------------------------------------
SPEAKER NOTES: [2-3 sentences for teacher -- NOT on slide.
Real-life analogy / Did You Know fact / exam tip / story.
EXCEPTION -- on Concept Practice and Exit Ticket slides the notes instead carry the COMPLETE step-by-step solution / answer + explanation (code may span many lines).]
+=======================================================+

================================================
SECTION D -- MANDATORY SLIDE SPECIFICATIONS
================================================

TITLE SLIDE (slide 1)
  Layout     : Full-bleed Dark (#0D1B2A background)
  Topic name : "String operations Theory" -- 54 pt Bold Cyan Electric (#00D4FF)
  Sub-line 1 : "XII CS Computer Science" -- 32 pt White
  Sub-line 2 : "CBSE Board | Lecture 8" -- 24 pt Slate Mist (#C9D4E0)
  Motif      : semi-transparent { } bracket centred background (15% opacity)

AGENDA (slide 2)
  Layout     : Left Icon+Text
  One row per subtopic below: icon-circle + subtopic name + time estimate

PRIOR KNOWLEDGE CHECK (slide 3)
  Layout     : Callout Box centred
  Single question in large rounded rectangle
  Badge      : "Think -> Pair -> Share" top-right
  Speaker notes: real-life analogy (NOT on slide)

CONTENT SLIDES (as many as the SLIDE COUNT rules in Section B require)
  Subtopics to cover (allocate slide count by EXAM FOCUS priority in Section F):
  • String operations

  Layout rules:
  * Avoid repeating the same layout twice in a row unless the second slide is a continuation, paired worked example, or necessary code-tracing slide. Clarity is more important than artificial layout rotation.
  * Theory    --> Callout Box for definition + Left Icon+Text for bullets
  * Examples  --> Code Card (dark card, Courier New 24 pt, keywords Cyan Electric)
  * Comparisons / look-alike concepts --> Two Column layout
  * Apply the EXPLAIN FOR UNDERSTANDING rule (Section B) to every theory slide
  * CRITICAL priority subtopics --> 2 slides (theory + worked example)
  * HIGH priority subtopics     --> 1 dedicated slide
  * MEDIUM priority subtopics   --> 1 bullet on a shared slide, UNLESS it has
    multiple distinct cases (Section B), then give it its own slide too

COMMON MISTAKES & EXAMINER TRAPS (right after all content slides)
  Layout     : Warning Banner
  Accent     : left thick border #E74C3C (4 pt) on each bullet card
  Title      : "DON'T MAKE THESE MISTAKES" -- 44 pt Bold Red
  EXACTLY 3 bullets -- specific examiner traps with red alert icon

CONCEPT PRACTICE -- THIS IS A THEORY LECTURE: no PYQ wording anywhere on these slides
  (4 slides, 1 self-generated question each, EASY -> TOUGH)
  Layout     : Exam Spotlight (large card, question text centred)
  Show ONLY  : question text (32 pt) + pedagogical marks badge such as '1M', '2M', or '3M' (Ocean Blue) + "Practice Question" badge
  The marks badge is for classroom practice only, not copied from any previous question.
  NEVER show : a real year badge, the "Representative PYQ-pattern question" label, or the
               word "PYQ"/"previous year question" anywhere on the slide
  Content    : every question must be SELF-GENERATED and worded purely about the concept
               itself -- informed by the private exam-importance analysis in Section F, but
               never reproducing, paraphrasing, or labelling an actual board question
  ANSWER ONLY IN SPEAKER NOTES -- NEVER ON SLIDE
  Order      : Easy -> Medium -> Hard; within each difficulty, 1M -> 2M -> 3M -> higher
               (see CONCEPT PRACTICE RULE in Section F)
  Placement  : after Common Mistakes and before Key Takeaways
  Students solve in ~90 seconds, then teacher reveals from notes

KEY TAKEAWAYS (second-to-last slide)
  Layout     : 3-Icon Grid (dark #0D1B2A background -- matches title)
  3 equal columns: large icon + 1-line heading (28 pt Bold) + 1-line summary (24 pt)
  EXACTLY 3 takeaways

EXIT TICKET (last slide)
  Layout     : Callout Box centred
  EXACTLY 1 MCQ or fill-in-the-blank -- question 32 pt, options 28 pt
  Timer badge: "60 seconds" top-right (Cyan Electric)
  ANSWER + EXPLANATION ONLY IN SPEAKER NOTES

================================================
SECTION E -- ENGAGEMENT RULES (MIN 2 IN SPEAKER NOTES)
================================================

1. Prior Knowledge Check slide: real-life analogy -- NOT textbook language
2. One slide: "Did You Know?" fun fact in speaker notes
3. One code slide: "Guess the Output?" -- ask class before revealing
4. Colour-coded bullets: red = warning, green = tip/example, blue = definition
5. Common Mistakes slide: one "Examiner Trap" with specific wrong answer students typically write

================================================
SECTION F -- EXAM FOCUS (WEIGHT SLIDES BY EXAM IMPORTANCE)
================================================

Board exam appearances: 28 times (2021-2026) | Total marks tested: 35M

DECK INTENT: build this as the POLISHED, EXAM-FOCUSED version of the study
notes — cover EVERY examiner-tested concept below (not just definitions),
and lead with the CRITICAL + CONFUSING concepts, giving them the most slide time.

TOP PRIORITY -- CRITICAL & CONFUSING CONCEPTS (open the content with these):
  ! String operations — asked as MCQ/Output Prediction/Short Answer; at 1,2,3M; 28x repeated --> own theory + worked-example slide; if it has a look-alike, use a Two-Column 'X vs Y' compare slide.

SUBTOPIC PRIORITY (allocate slide count by this ranking — see SLIDE COUNT rules in Section B):
  CRITICAL --> 2 slides: theory + worked example
    * String operations — 28x in exams, 35M total (years: 2026, 2025, 2024)

===========================================
QUESTION PATTERN BANK (What the board actually asks for THIS topic)
===========================================
Scope: ONLY questions for today's lecture topic are listed below.
DO NOT import questions from other topics or chapters.
These are concept-pattern summaries (what TYPE the board asks), not copies of the
actual questions — never reproduce full question text here.

### Concept: String operations
  Pattern: MCQ=20, Output Prediction=6, Short Answer=2 | Marks: 1M=24, 2M=1, 3M=3 | Total: 28 questions
  [MCQ] [1M] [Easy] × 3
    → Core concept of String operations
  [MCQ] [1M] [Easy] × 17
    → Output/result interpretation for the current concept
  [Output Prediction] [3M] [Medium] × 3
    → Output/result interpretation for the current concept
  [Short Answer] [1M] [Easy] × 2
    → True/False: core concept of String operations
  [Output Prediction] [1M] [Easy] × 2
    → Output/result interpretation for the current concept
  [Output Prediction] [2M] [Easy]
    → Output/result interpretation for the current concept


===========================================
IMPORTANCE ANALYSIS (allocate teaching time by this ranking)
===========================================
| Rank | Concept | Score | Times Tested | Total Marks | Recent Years | Priority |
|------|---------|-------|-------------|-------------|--------------|----------|
| 1 | String operations | 112 | 28 | 35M | 2026, 2025, 2024 | CRITICAL |

EXAMINER FINGERPRINT -- TRAPS TO COVER INTERNALLY

Use this section only for internal slide planning. Do not print this
heading or these internal labels on slides.

For this lecture, the deck must strongly cover these traps:

No static trap list exists yet for "String operations". Self-generate 4–7 traps from:
- actual question patterns for String operations
- common wrong assumptions students make about this concept
- output-tracing traps
- syntax-vs-runtime traps
- comparison traps
- order/sequence traps

* Common Mistakes slide must select the top 3 traps from this Examiner
  Fingerprint list.
* Concept Practice slides must together cover at least 4 traps from this list.
* Content slides must teach the traps before practice slides test them.

SELF-GENERATED PRACTICE-QUESTION SEEDS
PRIVATE ANALYSIS INPUT ONLY -- NEVER PRINT ON SLIDES

The seed text is only a concept/trap reference. The generated deck must
create new questions using different wording, different code/data where
possible, and no source-year references.
  THIS IS A THEORY DECK. The 4 question(s) below are PRIVATE INPUT —
  do NOT reproduce, paraphrase, or show any of this text verbatim on a slide, and
  NEVER show a real year/marks-from-PYQ badge or the word "PYQ" on any slide.
  For each seed, self-generate a NEW practice question that tests the SAME concept
  and trap, worded purely about the concept itself (not as board/PYQ practice).
  Order the self-generated questions Easy -> Tough, 1M -> 2M -> 3M -> higher.

  Seed 1. [INTERNAL ONLY -- never shown on a slide] [1M] [Easy/MCQ] Concept: String operations
  ```
  Which of the following operator cannot be used with string data type?
  a) +
  b) in
  c) *
  d) /
  ```
  Seed 2. [INTERNAL ONLY -- never shown on a slide] [1M] [Easy/MCQ] Concept: String operations
  ```
  Find the output of the following code:
  Name="PythoN3.1"
  R=""
  for x in range(len(Name)):
      if Name[x].isupper():
          R=R+Name[x].lower()
      elif Name[x].islower():
          R=R+Name[x].upper()
      elif Name[x].isdigit():
          R=R+Name[x-1]
      else:
          R=R+"#"
  print(R)
  a) pYTHOn##@
  b) pYTHOnN#@
  c) pYTHOn#@
  d) pYTHOnN@#
  ```
  Seed 3. [INTERNAL ONLY -- never shown on a slide] [1M] [Easy/MCQ] Concept: String operations
  ```
  Select the correct output of the code:
  a = "Year 2022 at All the best"
  a = a.split('2')
  b = a[0] + ". " + a[1] + ". " + a[3]
  print(b)
  a) Year . 0. at All the best
  b) Year 0. at All the best
  c) Year . 022. at All the best
  d) Year . 0. at all the best
  ```
  Seed 4. [INTERNAL ONLY -- never shown on a slide] [1M] [Easy/MCQ] Concept: String operations
  ```
  Which of the following statement(s) would give an error after executing the following code?
  S="Welcome to class XII"  # Statement 1
  print(S)                  # Statement 2
  S="Thank you"             # Statement 3
  S[0]= '@'                 # Statement 4
  S=S+"Thank you"           # Statement 5
  a) Statement 3
  b) Statement 4
  c) Statement 5
  d) Statement 4 and 5
  ```

SLIDE WEIGHTING RULE:
  CONFUSING/CRITICAL concepts --> FIRST content slides; own theory slide + own
                                  worked-example or 'X vs Y' compare slide
  HIGH subtopics     --> own slide
  MEDIUM subtopics   --> 1 bullet max on a shared slide
  Every concept named in the QUESTION PATTERN BANK above MUST appear on a slide —
  a concept the board has actually tested may NEVER be dropped to save slides.

CONCEPT PRACTICE RULE:
  Make EXACTLY 4 self-generated Concept Practice slides unless the
  user explicitly requests a shorter deck -- this is the one authoritative count
  for this section.
  Each practice slide must contain ONE original question only.
  Answer and full explanation must appear only in speaker notes.
  The questions must progress Easy -> Medium -> Hard/Tough.
  Together, the questions must cover the most important examiner traps from
  the EXAMINER FINGERPRINT section above.
  For any question needing a skill NOT covered in this lecture's content slides,
  add a 1-line "Quick recall:" reminder of that skill in the speaker notes BEFORE
  the solution -- never leave students to bridge that gap alone.

NO PREVIOUS-QUESTION LEAK RULE:
  This is a theory deck.
  Use the private exam-analysis input only to decide emphasis, traps, and
  practice coverage.
  Never reproduce, paraphrase, or display an actual previous board question on
  any slide.
  Never show a real year badge.
  Never show "marks-from-previous-question" metadata.
  Never use the labels "PYQ", "previous year question", "PYQ-pattern",
  "PYQ-style", or "Representative PYQ-pattern question" anywhere on a slide.
  Every practice slide must read as original classroom practice content.
  Full answer and explanation must appear only in speaker notes.

================================================
SECTION G -- QUALITY CHECKLIST (VERIFY BEFORE OUTPUT)
================================================

Visual Checks:
  [ ] Title font >= 44 pt on every slide
  [ ] Body font >= 28 pt on every slide
  [ ] Code font >= 24 pt inside dark card only
  [ ] No font below 24 pt anywhere
  [ ] Every slide has icon, shape, code card, or diagram
  [ ] No unnecessary repeated layout; continuation, paired worked-example, and necessary code-tracing slides may repeat layout.
  [ ] Sandwich: dark Title -> light content -> dark Key Takeaways -> light Exit Ticket
  [ ] { } bracket motif on every content slide
  [ ] NO accent lines under titles
  [ ] NO full-width colour bars or stripes
  [ ] NO cream/beige backgrounds
  [ ] Bullets left-aligned (titles centred only)
  [ ] ONE clear focal point per slide (one hero element, one accent moment)
  [ ] Objects snapped to the grid -- tops/left edges aligned, nothing free-floating
  [ ] Accent colour <= 10% of slide area; cards use 6-8% tints, not saturated fills
  [ ] Every slide's visual carries meaning (no decorative icon-circles / clip-art)
  [ ] At least 60% of each content slide is background + breathing space

Content Checks:
  [ ] CRITICAL/HIGH subtopics in Section D have dedicated slides
  [ ] MEDIUM subtopics are covered on shared slides unless they have multiple
      distinct cases
  [ ] Multi-case subtopics (list, tuple, dict, and string behaviour) have EACH case
      covered, not compressed into one slide
  [ ] Every theory slide has a plain-English restatement AND a concrete example
  [ ] No slide has more than 3 bullets
  [ ] No bullet longer than 10 words
  [ ] Every code example on its own Code Card slide
  [ ] Common Mistakes slide has EXACTLY 3 examiner traps (red accent)
  [ ] Concept Practice slides: self-generated question + marks badge only -- NO real year, NO "PYQ"
      wording, NO "Representative PYQ-pattern question" label anywhere -- answer ONLY in speaker notes
  [ ] Concept Practice slides ordered easiest-to-hardest
  [ ] Key Takeaways slide has EXACTLY 3 takeaways in 3-Icon Grid layout
  [ ] Exit Ticket has 1 question with answer ONLY in speaker notes
  [ ] All speaker notes include teacher dialogue (EXCEPT Concept Practice & Exit Ticket, whose notes carry the full solution/answer instead -- Section C)
  [ ] Minimum 2 engagement techniques across speaker notes

Layout Safety Checks:
  [ ] Every slide uses 16:9 widescreen canvas
  [ ] All objects keep at least 0.35 inch margin from slide edges
  [ ] Title stays within y=0.35-1.15 inch and wraps to max 2 lines
  [ ] Body starts at y >= 1.45 inch; large cards/callouts at y >= 1.55 inch
  [ ] Badges stay in the top-right badge zone and never touch title/body
  [ ] No text, badge, icon, card, code block, or diagram overlaps another object
  [ ] No PowerPoint auto-fit has reduced required font sizes
  [ ] Continuation slides are used whenever content would otherwise crowd
  [ ] Rendered slide images have no clipped, hidden, overlapping, or tiny text

34733 chars Customise board, duration & level

String operations Theory

Mark Lecture as Missed

Reset All Progress?